Electron-discharge device



Jan. 29,1929.

1,700,373 A. MAVROGENIS ELECTRON DISCHARGE-DEVICE Filed Jan. 6, 1927 3 Sheets-Sheet 1 Jan. 29, 1929.

' A. MAVROGENIS ELECTRON DISCHARGE DEVICE 3 Sheats-Shee t 2 Filed Jan. 6, 1927 Jan. 29, 1929.

A. MAVROGENIS ELECTRON. DISCHARGE DEVICE Filed Jan. '6, 1927 Patented Jan. 29 1929.

' Ams'ro'ri: uavnoenms, or MILWAUKEE, Wisconsin.

ELEGTBOiN-PISCHARGE DEVICE.

.- Application filed January 8,1927. 7 Serial K0 1595313.

This invention relates to electron discharge devices, and is particularly directed to an electron discharge device in which all of the parts may be energized from commercial al'-. ternating current mains.

Further objects arecto provide a device of this nature which may be used in radio work as a detector or amplifier without the necessity of using either filament or plate batteries, and in which all hum or disturbance is eliminated. v i

This invention deals with the general type of electron discharge device such' as disclosed in my Patent No. 1,570,444 of January 19, 1926, for wireless apparatus; and as disclosedin my patents for electron discharge devices No. 1,638,499 of August 9, 1927, No.

1,616,914 of February 8, 1927, No. 1,629,171 of May 17, 1927, and Patent No. 1,660,803 of February 28, 1928, for wireless receiving apparatus; and in my co-pending' application, Serial No. 145,940, filed November 3, 1926, for-electron discharged devices.

In general, thisinvention has for its ob-,

jects the provision of a novel formof electron discharge device in which an audion, a cur rent limiting device or its equivalent, and a vapor discharge rectifier, are associated and are positioned in the same'vessel; and to provide-a novel form of unitary electron dis charge device in which the ionic rectifier has a very low internal voltage drop. v

A further object of this invention is to provide' a unitaryclectron discharge device in which a novel form of equipotential cathode is employed, and which has a much lower ionization voltage than in the case of I gaseous discharge cathodes. a Further objects are to provide a unitary electron discharge device in which the ionic rectifier has a plurality of functions as it not only performs its functions as a rectifier, but also'acts as a heater for the cathodes of the other cooperating parts; that is to say, as a heater for the cathodes of the audion and current limiting device. I 1

Further objects are to provide'an electron dischar e device in which the number of mechanically distinct, but electrically cooperating parts is reduced to a minimum, although an audion, a current limiting or voltage limiting device, and an ionic rectifier are provided.

Further objects are to provide a unitary electron discharge device in which all of the parts are more rugged and mechanically stron er, and are not so liable to break in hand ing or shipping, or to burn out in use.

as with the other types of electron emission devices employing a heated filament and the associated parts. Embodiments of the invention are shown in the accompanying drawings in which:

Figure 1 is a diagrammatic view of one form of the invention employing a halfcycle vapor rectifier;

Flgure 2 shows a further form of the inprovided for heating the rectifier bulb;

Figure 3 is a view showing a further form corresponding to Figure 1, but showing a full wave rectifier and a diflerent type of heating means;

Figure 4 shows a form of the invention corresponding to Figure 2 by employing a voltage limiting device;

Figure 5 is a further form of the invention in which a separateeheater is provided Figure 7 is an enlarged view of the recti-' 'fier as used in the form shown in Figure 3;

Figure 8 is a view of the cathode heater employed in the form shown in Figure 5.

vention'in which a difierent type of means is Referring to the drawings, particularly Figure 1, itwill be seen that the device comprises an evacuated vessel 1 having a neck or base portion 2 separated from the main body of the vessel by the wall 3. It is intended that these devices be constructed in the shape, for. example, of the usual vacuum tubes employed in the radio work in which the part 2 which corresponds to the bottom of the tube is ordinarily inserted in the tube socket, al-

though, of'course, other shapes may be employed in the drawings. It is to be understood that the prongs preferably extend out through the bottom of the device, so that the device may be inserted in the usual tube 1 socket, although for convenience of illustration, the simplest form of diagrammatic showing has been employed.

The rectifier is a half cycle vapor discharge rectifier and comprises a vessel 4 of high resistance characteristics andof good dielectric properties, and of non-porous material such, for instance, as quartz, silica, glass, etc. and hermetically sealed. An anode 5 is sealed in the upper portion of the vessel 1, and in the lower bulb-like portion 6 a pair of electrodes 7 are positioned. The anode in reference to the surface of the cathode formed by a pool of mercury or other readily vaporizable material is extremely small, and is formed of a metal having a high melting point, such as molybdenum, tungsten, carbon, iron, aluminum, platinum, tantalum, copper, constantan, or the like. This anode is connected by means of the'conductor 8 to one of the alternating current mains 9 of commercial voltage and frequency, such connection extending through one of the prongs ofthe device. It is intended that the conductor and the anode be relatively rigid so that they will act as a support for the rectifier.

The cathode, as stated, is formed of relatively low melting point material or else one which emits vapors at a relatively low temperature, such vapors being the ionizing agents in therectifier. In place of mercury other material may be used, such as alkali metals, for example, potassium, sodium, rubidium, caesium, lithium. One of the electrodes 7 is connected by means of the conductor 10 with one side of a storage condenser 11. The other side of the storage condenser is connected to the conductor 12 and through an adjustable resistance 13 to the other main 14. The other electrode 7 is connected directly through a limiting resistance 15 to the other side 9 of the main; that is to say, is connected within the base portion 2 of the unitary de-- vice to the conduct-or 8 which leads to the main 9. Further, it is to be noted from Figure 1, that the conductor 10 leads also to the anode 16 of the current limiting device, the cathode 17 of which is heated by means of the heat generated by the rectifier. This cathode may be-a sleeve surrounding a portion of the rectifier vessel and may be formed as a separate metal member or as a conducting and electrically active coating thereon, as described in detail in my co-pending application, Serial No. 150,644. filed November 26, 1926, for gaseous discharge device.

The cathode '17 of the thermionic current limiting device. is connected to the conductor '19 which leads to the plate or anode 19 ot' the audion. The cathode 20 of the audion is formed in a manner similar to the cathode 17, just described. and is heated by the heat generated b the rectifier. This calhOde is also connected by means of a conductor 21 to a translating device, such as the primary 22 of 'a coupling transforn'ier. The other side of this coupling transformer is connected by means of the conductor 23 to the conductor 12, as previously described, which leads to one side of the storage condenser 11. Further, it is to be noted that the interposed grid 24 is connected to one of the input terminals of the transformer secondary 25 or other similar device, and the other side of this transformer is connected to the cathode 20 of the electrodes 7 causes the vaporizable material to assume an active electron emitting condition and, consequently, a discharge is started between the anode 5 of the rectifier and its vaporizable cathode. In operation, the cathode of the rectifier is heated continuously at a suitable voltage by the alternating current througl'i the electrodes 7 and the correct voltage is secured by the interposition of the resistance 15. This material emits vapors which permit current to flow from the anode to the cathode, thus allowing an arc to form between such anode and cathode, the are being a source of gaseous ions. -The cathode being of much larger active surface than the anode, a unidirectional flow of current will take place from the anode to the cathode. The vessel becomes hot because of the arc and because of collision of the gaseous molecules and electrons and ions and, consequently, this heat is furnished in the normal operation of the rectifier. The heat is not wasted. but is used to heat the cathodes of the thermionic current limiting device and of the audion. Preferably, these cathodes are coated on their outer surfaces with a thermionically active material.

It is preferable that the rectifier vesselmaintains a high vacuum, when in a cold sired for the operation of the audion. In

this case, no harm comes to the apparatus, but merely an increase in its output, as distinguishing it from any of the conventional types of electron discharge devices, in which any material variation in the filament voltage will result in ruining the device.

Figure 2 shows substantially the same construction as that illustrated in Figure l, with,

however, the principal exception that the heating of'the cathode contained in the rectificr vessel 4 is done by means of an external heater 28 which is connected through a. re sistance of proper value 15 to the input terminals of the apparatus, such input terminals being connected through an adjustable resistance 30 with the alternating current mains 1'4 and 9, as previously described. Otherwise, the connections for this form of the invenpreviously decoating may be formed by any of the processes disclosed in'my co-pendingapplications, Serial No. 140,848, of October 11, 1926, for

' cathodes and method of making the same;

Serial No. 150,644, filed Nov. 26, 1926, cathodes for electron discharge devices, and Serial No. 154,199, filed December 11, 1926, for cathodes and method of making same.

Figure 3 shows a further form of the invention, very much like that described in connection with Figure 1 except that a manually operable switch or cut-out 31 is provided for controlling the current to the electrodes 7 leading to the cathode of the rectifier 4. This rectifier is provided with a bulb 6, as previously described, for containing the readily vaporizable material used as cathode. The upper end of the'rectifier carries apair of anodes indicated by the reference characters 32 and 33. These anodes are connected to the conductors 34 and 35 which leads outwardly through the device, and are connected to the mains 14 and 9 through the control resistance 13, as previously described. The

storage condenser 11 is connected in the same manner to the anode 16 of the current limiting device at one end. The other end of the storage condenser 11 is conneeted through an inductance 36 to the conductor 37, and is also connected to the center point of a re sistance 38 bridged across the conductors 34 and 35.. The other portions of the apparatus are the same as previously described in connection with Figure 1.

In each of the forms described, the rectifier, the current limiting device, and the audion are carried within the evacuated chamber 1 of the device, whereas the several re- 1 sistances and condensers, and in the last described form the inductance and cut-out switch are carried in the bottom portion 2- leads to the common conductor 37 for the bypass condenser 26, the by-pass resistance 27, and the neutral point of the resistance 38, as well as one end of the inductance 36.

In the form of the invention shown in Figure 4, the rectifier 39 is similar to that described in connection with Figure 2, and is heated by means of the resistance member or heater 28, such heater being connected to the mains 9 and 14 through a variable resistance 13. However, the thermionic current limiting device is replaced by a voltage limiting device which is contained in a separate compartment, as indicated at 41, distinct from the compartment 42 containing the audion and the rectifier. The compartment 42 may be either-highly exhausted, or else filled with any inert gas at any suitable pressure, as is the practice for gas radio tubes. The compartment 41 may be provided with any inert gas at suitable pressure, such as neon, argon, helium, etc. The pressure, of course, is dependent upon the nature of the electrodes in this compartment, and the minimum pressure is usually from a small fraction of a millimeter to twenty millimeters of mercury when the device is intended to be operated from 110 to 120 volts alternating current mains.

Further, it is to be noted that the voltage limiting device is provided with a relatively small anode 43 for a relatively large cathode 44 andisconnected to the cathode of the rectifier through a resistance 45. Further, it will be noted that the voltage limiting device including the members 43 and 44 and the resistance 45,. is bridged around the storage condenser 11 It is also to be noted that the plate 19 of the audion is connected at the common point of union or connection of the an? ode 43 of the voltage limiting deviceand the resistance 45, so that the voltage limiting device maintains a constant voltage at the anode or plate of the audion. The by-pass condenser 26 and by-pass resistance 27 are employed, as previously described.

Figure 5 shows diagrammatically a somewhat difl'erent form of the apparatus in which a separate heater 46 is employed for the cathode 20 of the audion and a distinct rectifier 47 is employed. The construction of the rec-. tifier 47 and the heater 46 may be identical and similar to the rectifiers previously described. The current from the rectifier cathode passes to one side of the storage condenser 11, the other side of such condenser being connected to the common conductor 48.

The cathode of the rectifier 47 is also connected through a ballast resistance 49 to the plate 19 of the audion, the by-pass condenser 26 and the by-pass resistance 27 being connected around the audion, as previously described. Preferably, the audion, its heater,

and the rectifier, are located in one conipartment 50 and the ballast resistance 49 located in another con'ipartn'ient 51 distinct from the bottom portion 2 of the device.

In this form of the invention, it is to be noted that the ionic rectifier and heater are "not provided with, auxiliary heatersof any type; it is, therefore, necessary to provide for the self-starting of these device. These devices are characterized by a very low internal voltage drop and, therefore, the auxiliary heating means is dispensed with. Further, these devices are so constructed that a relatively higher rectified current from the same applied voltage is secured than in the other forms of the device, described above. Preferably, the cathode is composed of an elec-' tropositive vaporizable material, such as any alkali metal, for example, potassium, or any alloy thereof, or any of the metals mentioned above. While the anode is formed of a highly electronegative metal, such as copper or constantan, for instance. The vessel is filled with a rare gas, such as argon, helium, neon, krypton, or the like. The pressure of the gas is to be adjusted to produce a discharge for a definite voltage at the anode, said pressure depending upon the nature of the gas employed, the nature of the electrodes, and the minimum plate voltage.

The ballast resistance 49 and the gas in the compartment 51 may be of any of the Wellknown types to secure a substantially constant current action for the device.

Figure 6 shows to an enlarged scale one form of the vapor rectifier and multiple equipotential cathodes. This rectifier is similar to the rectifier illustrated in Figures 2 and 4, and comprises a glass-like vessel 52 having a bulb 53 at its lower end which con-' tains the cathode of Vaporizable material. The upper end of the rectifier has the anode 54 sealed therein, as previously described, and the bulb portion has the electrode 55 scaled therein and projecting into the cathode of vaporizable material 56. The lower portion of the tube is provided with the equipotential cathode of the current limiting device, and this cathode consists of a coating 57 formed of metal and a thermionically active external coating 58 thereon. These coatings may be formed by any of the processes disclosed in my copending applications, Serial No. 140,848, filed October 11, 1926 for cathodes and method of making the same, Serial No. 150,644, filed November 26, 1926 for cathode for electron discharge devices, and Serial No. 154,199, filed December 11, 1926, for cathode and method of making the same.

The first coating is of electrically conductin'g material and contains platinum, palladium, rhodium, ruthenium, iridium, osmium, nickel, gold, silver, iron compounds, or mixturcs of any two or more of these metals.

This metallic coating is itself coated with or formed with any low electron affinity oxides or eonwpoun ls,'such as barium, strontium, calcium, barium, nitrate, or the like, as disclosed in the above mentioned applications. Further, it is to be noted that a lead 59 is embedded in the metallic coating 57 and may, it desired, be partly sealed to the glass. This lead constitutes the lead to the cathode of the current limiting device.

The rectifier is also coated with an upper inner member 60 similar to the member 57 and with an outer coating 61 similar to the member 58 and is provided with lead 62 secured in a manner similar to that employed for the lead 59. The upper portion constitutes the cathode of the audion.

The rectifier tube is provided with some means for separating the two cathodes. For example, it may be provided with an enlargement, as indicated at 63. Preferably, the end portions of the glass tube are formed opaque so as to prevent loss of energy-by radiation, such as, for example, by radiating light or heat waves, such opaque portions confining this radiant energy within the rectifier tube.

The resistance used for heating the cathode is indicated at 64 and is similar to the resistances described in connection with Figures 2 and 4.

It is obvious that the leads 59 and 62 may be carried in grooves, if desired, formed on the outer surface of the glass tube and may be readily sealed to the glass, as previously described. I

' Figure-7 shows afurther form of rectifier and multiple equipotential cathode, such, for example, as employed in the structure shown in Figure 3. This rectifier comprises the glass vessel 65 which carries metal sleeves 66 and 67, preferably coated with thermonically active material and forming respectively the cathodes for the andion and for the current limiting device. The glass tube is preferably blown outwardly intermediate its ends to provide an enlargement for separating the cathodes of the current limiting device and of the audion. The rectifier is a full-wave rectifier and is provided with the two anodes 68 and 69 and with a bulb 70 at its lower end which may contain apool of mercury 71. A pair of electrodes 72 and 73 project into this pool of mercury and are sealed in the glass bulb. Obviously-,'other vaporizable material, as described above, may be substituted for the mercury, and the anodes may be formed of material as de- 76 to prevent the passage of the cathode matcrial 77 upwardly, if the tube is inadvertcntly tilted. An electrode 78 is sealed in the lower end of the bulb and extends into the cathode material 77. An anode 79 is sealed in the upper end of the bulb. The cathode is formed of any alkali metals or alloys thereof, as described above. The anode 7 9 is formed of a highly electroncgative material, such as copper, constantan, orother material, as described above, and preferably, an inert rare gas is carried within the tube, such gas being for example, neon, argon, helium, or the like. This rectifier is self starting and has a very small percentage of voltage drop and gives a relatively large rec tified current. The audion cathode or equipotential cathode may surround this rectier,-as previously described,'and may take any of the forms previously described. In the form shown in Figure 8, a single cathode is shown, composed of a metal sleeve 80 coated with a thermionically active coating 81 closely surrounding the rectifier.

This device is similar'to the heater 46 or the rectifier 47 shown in Figure 5. However, it is to be noted, that in Figure 5 a separate heater is employed for the cathode of the audionr Obviously, the device may be used as a combined rectifier and heater without employing an auxiliary separate heater, as shown in Figure 5.

It is to be understood that each of theforms shown in Figures 6,7, and 8, may be employed either exclusively as rectifiers or as vapor or vapor-gaseous cathodes, or even as a double duty rectifier and cathode.

When-the devices function in the last capacity, the electron discharge device is reduced to its simplest form, It is to be noted that the novel forms of unitary devices not only are adapted to operate directly from city malns of the usual voltages, but also the much higher voltages if so desired, and to stillremain of the four-prong type since both the rectifier and the heater constitute a single unit and are energized always at the same voltage. Further, it is to be notedthat the serious disadvantage of burning out of the.

- filament limits thegoperative voltage that may be associated with electron discharge devices of the usual type so that a slight variation in voltage results in ruining the tube.

7 However, devices disclosed by this invention may be designed for must higher voltages as the devices are adapted to operate at voltages considerably in excess of the voltage of the city mains without affecting the life of the electron discharge devices. The only result in this case is to increase the output power of the tube, which obviously may be desirable.

This invention may be variously embodied and thenovel form'of electron-discharge device is not limited to any particular type of either vapor discharge rectifier o'r vaporgaseous discharge rectifier since any vapor discharge rectifier provided with an ionizing agent in the form of either a vapor, gas, or both, can be embedded in the unitary device. It is, therefore, to be understood that the term vapor discharge rectifier as used in the claims, is intended to cover any rectifier using either vapor or gas or gases and vapors of an arc discharge, glow discharge, or an arc-glow discharge type, and further, it is to be' understood that the invention is not limited to the particular nature of cathode and anode, or of the vaporizable material, or of the pressure of the gases employed therewith, nor is it limited to the shape of the electrodes or the vessel.

It will thus be seen that although the invention has been described in considerable detail, such description is intended as illustrative rather than limiting as the invention may be variously embodies and as the scope of such invention is to be determined as claimed.

I claim:

.1. A unitary electron discharge device including an hermetically sealed vessel, an audion having an equipotential cathode, an

anode, and a grid interposed between said cathode and anode, a rectifier for supplying said anode and for heating said audion cathode, and means for smoothing out pulsations in the energy supplied said audion anode, said audion and said rectifier being located in said "essel, said equipotential cathode having a single 'duty of emitting electrons for said audion, and said rectifier anode being mechanically distinct from said audion cathode.

2. A. unitary electron discharge device-including an evacuated vessel, an audion having an equipotential cathode, an anode, and a grid interposed between said anode and cathode, a vapor discharge rectifier for supplying said audion anode, and for heating said audion cathode, said rectifier having a cathode'and an anode mechanically distinct from said audion cathode and means for smoothing out pulsations in' the energy supplied said audion anode, said audion and said rectifier being located in said evacuated Vessel, said means including a current limiting device enclosed within said vessel and, having an anode and a cathode heated by said rectifier.

3. A unitary electron discharge device including an hermetically sealed vessel, an audion having an equipotential cathode, an anode, and a grid interposed between said anode and cathode, a vapor discharge rectitier for supplying energy to said audion anode and for heating said audion cathode, said rectifier having a cathode and an anode mechanicallydistinct from said audion cathode, means for controlling the energy supplied said audion anode, and a storage condenser cooperating with said rectifier and said controlling means, said audion, said means and said rectifier being located in said vessel.

4. A unitary electron discharge device in-- charge rectifier for supplying said audion anode and for heating said audion cathode, sad rectifier comprising a vessel enclosing a' ionizable material, and a plurality of electrodes mechanically distinct from said audion cathode, means for smoothing out the energy pulsations from said rectifier and being connected between said rectlfier and said audion, and a condenser having one side connected to said audion anode and a second side connected to said smoothing means, said audion and said rectifier being located in said envelope.

5. A unitary electron discharge device 1ncluding an hermetically sealed vessel, an audion having an equipotential cathode, an anode and an interposed grid, a full wave vapor discharge rectifier having a cathode and a pair of anodes mechanically distinct from said audion cathodes for supplying said audion anode and for heating said aud on cathode, said a'udion and said rectifier being enclosed within said vessel, and smoothing means for securing a flow of current, in operation, from said audion anode to said audion cathode independent of the low frequency variation of the alternating current supplied said rectifier anodes, said means forming with said vessel a unitary structure.

6. In a device, an hermetically sealed envelope, a-vapor discharge rectifier enclosed within said envelope and including an vair tight vessel, a cathode of vaporizable material, and an anode located within said air tight vessel, a current limiting device provided with an anode and a cathode enclosed within said envelope for controlling the current supplied from said rectifier, said rectifier and current limiting device having a common terminal, and the the cathode of said current limiting device closely surrounding said air-tight vessel to be heated'by said rectifier.

7 In a device, an hermetically sealed envelope, an audion havingan equipotential cathode, an anode and a controlling element and enclosed Within said envelope, a vapor discharge rectifier enclosed Within said onvelope for supplying current to said audion anode and comprising an air tight vessel, an

anode and a cathodeof vaporizable material,

the electrodes of said rectifier being enclosed Within said alr tight vessel, and a pluraHy of external terminals carried by said envelope and connected to said audion and to said rectifier, said audion cathode closely surrounding said air tight vessel and being mechanically distinct from the cathode and anode of said rectifier and being insulated from the interior of said air tight vessel,

said audion cathode to be heated by said rectifier.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee, in the county of Milwaukee, and State of YVisconsin.

ARISTOTE MAVROGENIS. 

